let numSubarrayProductLessThank = function(nums, k){
    let len = nums.length
    let count =0
    let left = 0
    let product = 1
    for(let right=0; right<len; right ++){
        product *= nums[right]
        if(product >= k){
            left ++
            product = product/nums[left]
        }
        count += 1

    }
}